In the workforce it is easy to couch compulsory drug tests in terms of workplace health and safety, and in a relationship between adults, where the obligations are set out in law or employment contracts, an employee can either accept legal drug screening or go and work elsewhere.

But with parents and their teenage children it is different. The conventional wisdom is that the best way to protect our children from the dangers of drugs is to talk openly about drugs with them and create a relationship of trust. 

In the current climate of concern about the incredibly destructive nature of methamphetamine or ice, a parent who brought in the drug dog, found ice and sought treatment for their child would be vindicated and applauded.

One could also argue that a search of a teenager’s car or room conducted without their knowledge would cause no harm. If in the end no drugs are found and no-one is any the wiser the parent is left with peace of mind and a bill.

But what are the consequences of invading the privacy of a teenager unnecessarily? Depending on their age, most parents accept that teenagers are entitled to their own space and privacy. 

If that is breached and it turns out without justification, the consequences for that parent-child relationship could be great.

At the very least a parent would want a very strong suspicion indeed and a rational and measured response planned in case there was drug use detected.

Playing at policing is not a measure parents should embark on lightly.